With respect to a quinolinone derivative, general quinolinone derivatives such as 3-methoxy-4-hydroxy-1-methyl-2(1H)-quinolinone and 8-methoxy-3-methoxy-4-hydroxy-1-methyl-2(1H)-quinolinone have hitherto been known (see, for example, Non-Patent Document 1: “Journal of Heterocyclic Chemistry 22, pages 1087-1088, 1985 (J. Heterocyclic Chem., 22, 1985)”). However, such a document does not describe that these compounds are useful as a specific therapeutic agent.
Also there have been known quinolinone derivatives which have oxygens directly bonded to carbons at the 3- and 4-positions and also have an amino group at the 7-position (see, for example, Patent Document 1: specification of U.S. Pat. No. 5,942,521 and Patent Document 2: specification of U.S. Pat. No. 6,136,822). In these documents, although an antiallergic action and an asthma treating action of a quinolinone derivative having an amino group have been studied, a therapeutic action against specific symptoms of chronic obstructive pulmonary disease through no antigen-antibody reaction has never been studied and also it has never been known that such a quinolinone derivative is effective as a therapeutic agent for chronic obstructive pulmonary disease.
An object to be achieved by the present invention is to provide a therapeutic agent for chronic obstructive pulmonary disease, which has high safety and is effective on chronic obstructive pulmonary disease and also exhibits extremely excellent drug potency, and a method for treating chronic obstructive pulmonary disease using the same.